CANBERRA, Australia — Investigators searching for the missing Malaysian jet have concluded an area where acoustic signals were detected is not the final resting place of the plane after an unmanned submersible found no trace of it, the search coordinator said Thursday.

The U.S. Navy's Bluefin 21 finished its final underwater mission in the southern Indian Ocean on Wednesday after scouring 330 square miles, the Joint Agency Coordination Center said.

"The area can now be discounted as the final resting place" of the missing plane, the Australia-based center said in a statement.

The underwater search for the airliner, which vanished March 8 with 239 people on board en route from Kuala Lumpur to Beijing, will be suspended for a couple months while more powerful sonar equipment is brought in to search a much wider area of 21,600 square miles, based on analysis of satellite data of the plane's most likely course, the center said.

That analysis has led authorities to believe that Malaysia Airlines Flight 370 diverted sharply from its flight path and flew south to the Indian Ocean. But not a single piece of the missing Boeing 777 has been found in one of aviation's most baffling mysteries.

The news comes after the U.S. Navy dismissed an American expert's reported comments that acoustic "pings" heard in April did not come from the jet's black boxes.